Light freight, business use only between March and the end of November

Dear Sir/Madam,

I am a wasp exterminator as a secondary occupation. The wasp season starts in March and ends in late November, with a peak from June to late October. During those peak months, I use my light goods vehicle 95% for professional purposes, outside the peak season perhaps 70%, and from December to the end of February almost exclusively for private use, but then I also drive less. How can I best arrange my professional use % via dexxter? Also in terms of light cargo fuel? Thank you in advance!